Final answer:
Throwing a ball in the air is an example of a quadratic function/equation used in real life because the ball's trajectory follows a parabolic path described by a quadratic equation.
Step-by-step explanation:
The student has asked which of the following is an example of a quadratic function/equation in real life. Among the options provided, throwing a ball in the air is an example of a quadratic function/equation. This is because when you throw a ball, its path follows a parabolic trajectory due to the gravitational pull, which is well-represented by a quadratic equation of the form y = ax^2 + bx + c, where x represents time or horizontal distance and y represents vertical distance. On the other hand, baking a cake, drawing a straight line, and solving a crossword puzzle do not typically involve quadratic relationships. A straight line is a linear relationship (linear equation), and quadratic equations are not typically used to describe the other scenarios mentioned.